Use BackBlaze to backup your computer. Every few months, make sure that it works
Every private key must be protected by a password
All Macs should have FileVault enabled
Do not use public searchable services like Pastebin or gist to share sensitive code or data
Do not install any pirated software on your Mac or phone
Browser extensions can pose security issues, so only install extensions from the Chrome Web Store or the App Store. Be aware that extensions may change ownership or be taken over by malicious actors, so use as few extensions as possible. Do not use any browser extensions that can track typed keys, passwords or browser history. Using the 1Password browser extension is fine.